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Chladni Plate experiment makes for a jawdropping video

first_imgWe all know you can’t see sound, but you can certainly see the effects of it. 18th century physicist Ernst Chladni was one of the first to realize that when he devised an experiment to visualize the effect resonant vibration has on an object. The so-called Chladni Plates are still one of the most visually striking experiments in physics that can be performed without a face shield.Chladni used a flat metal plate covered with a dusting of sand. He ran a bow along the edge until the plate began to resonate. What he saw all those centuries ago is not terribly dissimilar to what you can see in the video below.Whereas Chladni used a bow, modern recreations of the experiment use an electronic signal generator. This allows the frequency of the sound to be precisely controlled and considerably higher. What you’re seeing here is a physical manifestation of a standing wave.As the sound waves resonate through the sheet of metal, they reflect back toward the source. The overlap of the waves causes an interference pattern of nodes and peaks. The places where the sand bunches up and appears to stand still are the nodes. As the frequency varies, the location of the nodes shifts.What’s especially cool about this experiment is how the nodal pattern grows increasingly complex as the frequency is cranked up. A higher frequency means more peaks in the sound wave, and thus more nodes in the resulting interference pattern.The way the sand skitters around the plate, transforming itself into increasingly complicated geometric shapes looks almost magical. But it’s really just science in action.last_img read more